Method of splitting stone



March 24, 1 3 J. c. ALEXANDER Patented Mar. 24, 1931 UNITED STATES PATENT OFFICE JOHN C. ALEXANDER, OF COLD" SPRING, MINNESOTA, ASSIGNOR TO COLI) SPRING GRANITE CO. INC., OF GOLD SPRING, MINNESOTA, A CORPORATION OF MINNESOTA METHOD OF SPLITTING STONE Application filed November 29, 1927. Serial No. 236,430.

This invention relates to a method and means for splitting stone. Some of the objects of the invention are: to split stone without waste; to avoid turning of the very heavy 5 stones during the splitting operation; and

to provide means whereby the splitting operation is successively performed from one or two finished sides of the stone, without scarring'or cracking any portion of the finished surfaces.

Features of the invention include the method of inserting the wedges, and the specific manner in which they are arranged, as well as all the details of construction.

Advantages of the invention will be set forth in the description of the drawings forming a part of this application, and in said drawings Figure 1 is a perspective view illustrating applicants method.

Figure '2 is a fragmentary plan showing how the wedges are applied and Figure 3 is a vertical section further illustrating the arrangement of the wedges at the beginning of the-splitting operation.

To thoroughly understand the advantages of applicants invention, it is thought neces- V sary to discuss certain methods now used for splitting stone, so that a comparison can be made which will clearly show the economic gain resulting from the'herein. described method and means. In one method, the stone is first finished on one side, and then bored from that same side, the bores being arranged in rows spaced in correspondence to the size of-the block to be out. These bores are ordinarily about three inches in diameter. Wedges are now introduced into 7 the bores to split the stone. However, that part of the stone which includes the bores is irregular and must be removed to finish the stone; There is considerable waste of material and time in performing these operations. In another method, one face of the block is first finished, and then the block turned, and grooved on the opposite side. The block is then turned again, and bores are made which lie in opposition to the grooves. The turning of the block, which may be from two to twenty inches thick and of a weight of two hundred seventy pounds pe'rcubic foot, is a laborious and time-consuming operation. There are, however, other objections, to-wit: that although splitting is supposed to take place between the bores and grooves, it often does not take place along those lines so that cracking of the stone at a point laterally of the groove results. The stone then has to either be refinished or discarded entirely, because it is not of the right width. The boring operation is time-consuming. Thus in the old methods the stone must be bored and/or turned. i

Applicants methods is shown in Figure l,

in which neither boring or turning of the stone is necessary. The stone in this instance is surfaced as at 10. comparatively deep and narrow grooves 11 are made as by sawing, to extend in direction of splitting.

.Wedge members 12 are then inserted, in

opposingly disposed but spaced relation. The height of these wedge members12 is less than the height of the groove, and the wedge elements ordinarily eXtendthe full length of the groove as shown in Figure 2. After the elements 12 have been placed substantially in a manner shown in Figure 3, wedge elements 13 are inserted and driven to split the rock. It will be seen that the first application of wedge force is adjacent the. top of the elements 12 but well below the level of the finished surface 10, so that nocracking off or marring of the corners of the planed groove is had. It will be'noted'that the forcing of a number of wedges 13 simultaneously may accomplish the results, or anumber of the wedges 18 may be placed and then successively given light taps to obtain gradual wedging action. The result is that the stone splits along the line G shown in Figure 1. However, if it should split along the line H, no harm is done inasmuch as it occurs only at the rough side of the block.

In practice the grooves 11 may be of any desired-width, length or depth, but are generally about a quarter of an inch wide and of a minimum depth of about one and one-half inches. Thus Waste is reduced .to a minimum, as compared with the boring method in which the bores are three inches in diameter.

The wedges or blades 12 may be of any length but are generally approximately one inch high, and approximately three thirty-seconds of an inch thick. The wedges 13 may be of any length but are generally approximately one-eighth of an inch thick by two or three inches high. The tops of the wedges 12, therefore, lie about one-half of an inch or more below the finished surface 10, and inasmuch as these wedges are generally beveled as at 15 and the elements 13 are generally beveled at 16, the initial wedging pressure is always applied a distance greater than one-half of an inch from the surface 10.

This arrangement has been found to posi-- tively preventcracking of the stone at points above the Wedges 12 and, therefore, is a valuable feature of the invention. The wedges are made of strap iron or steel.

In the present method, less space in the work room is required because no turning of the stone is necessary. The time of boring is saved as well as the material ordinarily wasted as the result of boring. Moreover,

grooving, turning and boring of the stone is unnecessary. The finishing and cutting operations may be performed at the same time, that is by a plurality of workmen operating on the same surface. There is no splitting toward the finished side, and where the block is finished on both sides the wedging operation can be simultaneously performed from both sides (by setting the block on edge). Thus, the splits from, the opposite side will register at some point intermediate the finished surfaces. In some instances, the grooves are only threesixteenths of an inch. In practice the ends of the wedges 13 are placed anywhere from three to eight inches apart. The closer the spacing, the more uniform the split. In hammering the wedges home, it has been found advisable to apply an even pressure to each wedge and to continue this application successively on the row of wedges 13, coming back to the starting place and continuing the operation until the splitting begins. As soon as splitting begins, the plates and Wedges are removed and pressure is applied on the granite, to finish the job. The removal of the wedges at this state prevents mutilation of the wedges 12 and 13. Any form of hammer can be used, and the wedges can be made of any cheap material, which will sufliciently withstand the hammer blows.

I claim as my invention:

1. A method of splitting stone which consists in finishing the face of the stone, forming a groove in this finished face, inserting a pair of fiatsurfaced wedges each of which has a relatively large area of engagement with the corresponding wall of the groove, and inserting a third flat surfaced wedge between the. hers S c manner as t ar panding pressure over a considerable area of the first mentioned wedges.

2. A method for splitting stone which consists in forming a groove, inserting a pair of flat surfaced wedges in a manner to obtain a relatively large surface engagement thereof with the faces of the grooves, and applying wedging force to separate the wedges.

3. A method for splitting stone which consists in forming a groove, inserting a pair of flat surfaced wedges in a manner to obtain a relatively large surface engagement thereof with the faces of the grooves, applying wedging force to separate the first mentioned wedges, and applying such force over a substantial area longitudinally of the wedges.

4. A method for splitting stone which consists in forming a groove, inserting a pair of flat surfaced wedges in a manner to obtain a relatively large surface engagement thereof with the faces of the grooves, and applying wedging force to separate thefirst mentioned wedges, successively at different points longitudinally of the wedges.

5. A method for splitting stone which consists in finishing a face of the stone, forming a groove in the finished surface, inserting a pair of flat surfaced wedges in a manner to obtain a relatively large surface engagement thereof with the faces of the grooves, and applying wedging force to separate the wedges, and applying such force only at points inwardly from the finished surface.

6. A method for splitting stone which consists in forming a rectangular groove, inserting a pair of flat surfaced wedges in a manner to obtain a relatively large surface engagement thereof with the faces of the grooves, and applying wedging force to separate the wedges. 7

7 A method of splitting stone which con sists in cutting a groove, inserting pairs of elongated plate-like wedges, and successively forcing another elongated plate-like wedge between each pair.

8. A method for splitting stone which consists in forming a groove, inserting a pair of elongated plate-like-wedges, applying wedge ing force successively at diflerent points, longitudinally ofthe wedges.

9. A method for splitting stone which consists in finishing theface of the stone, forming a rectangular groove in this finished face, inserting a pair of flat wedge plates in a manner to obtain a relatively large surface engagement thereof with the faces of the grooves, allat a point below the finished surface of the stone, and applying wedging force to separate the wedges with the force applied over a substantial area longitudinally of the wedges, and by successive application atdifferent points longitudinally of the wedges.

In witness whereof, I have hereunto set my hand this 23rd day of November, 1927.

J C. ALEXANDER. 

